Many studies (along with casual observation in any home with a teenager) have associated nighttime media use — video gaming, Internet surfing and TV time — with sleep deficits in teens. But the latest research fine tunes those findings, suggesting that while some types of media may indeed keep teens up too late, others may have no effect.

In a study presented Monday at the American Psychiatric Association’s annual meeting in Honolulu, researchers studying how media consumption affects adolescent sleep reported that video gaming and Internet use were associated with less sleep among teens, but TV watching was linked to slightly increased time in bed.

In addition, the researchers found, physical activity was also associated with increased teen sleep, confirming previous data that links exercise with better sleep.

Fewer than 10% of teens currently get the recommended nine hours of sleep each night, and students who spend more time connecting with friends online or playing video games at night are more likely to be in that sleepless group, says the study’s lead author Dr. Caris Fitzgerald, a resident physician in psychiatry at the University of Arkansas. “Gaming and computer use are more about the drive to stay awake,” she says. “They are more about arousal. Studies show that they are linked to heart rate variability, blood pressure changes, and changes in flight-or-fight responses.”

Working off the hypothesis that gaming and Internet use are engaging and stimulating activities, TV watching can be considered more passive, which may be why it was linked to slightly more hours of sleep among the teens surveyed in the study.

However, Fitzgerald says the study wasn’t designed to determine causality — in other words, the findings say nothing about whether it was the media use that determined how much sleep teens got, or whether the teens’ existing sleep patterns led to more or less computer use.

Even so, the results hint that there may be differences in the way social media influences sleep. “We live in a 24-7 society and that is not going to go away,” Fitzgerald says. “Moderation is the key, and we should pay special attention to the timing of social media exposure, and especially with regard to sleep, it may be important to minimize the effect of certain social media at night.”